package com.quan.bookmall.service;

import com.quan.bookmall.dto.CartItemDTO;

import java.util.List;

public interface CartService {
    
    List<CartItemDTO> findByUserId(Long userId);
    
    CartItemDTO addToCart(Long userId, Long bookId, Integer quantity);
    
    CartItemDTO updateQuantity(Long userId, Long bookId, Integer quantity);
    
    void removeFromCart(Long userId, Long bookId);
    
    void clearCart(Long userId);
} 